Contacts for semiconductor devices and methods of making thereof are disclosed. A method comprises forming a first layer on a semiconductor, the first layer comprising one or more metals; forming a second layer on the first layer, the second layer comprising the one or more metals, nitrogen and oxygen; and heating the first and second layer such that oxygen migrates from the second layer into the first layer and the first layer comprises a sub-stoichiometric metal oxide after heating. Exemplary embodiments use transition metals such as Ti in the first layer. After heating there is a sub-stoichiometric oxide layer of about 2.5 nm thickness between a metal nitride conductor and the semiconductor. The specific contact resistivity is less than about 7×10−9 Ω·cm2.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of fabricating a semiconductor device, the method comprising forming a first layer on a semiconductor, wherein the semiconductor comprises a III-V semiconductor, the first layer comprising one or more metals; forming a second layer on the first layer, the second layer comprising the one or more metals, nitrogen and oxygen; and heating the first and second layer, such that the first layer comprises a sub-stoichiometric metal oxide.
2. The method of claim 1 , wherein the one or more metals comprise titanium or zinc.
3. The method of claim 1 , wherein the heating is performed in an oxygen-free atmosphere.
4. The method of claim 1 , wherein the ratio of oxygen atoms to nitrogen atoms in the second layer is about 1:10 prior to the heating step.
5. The method of claim 1 , wherein the thickness of the first layer prior to the heating step is between about 1 nm and about 3 nm.
6. The method of claim 1 , wherein the thickness of the first layer prior to the heating step is about 2.5 nm.
7. The method of claim 1 , wherein the thickness of the second layer prior to the heating step is between about 2 nm and about 5 nm.
8. The method of claim 1 , wherein the first and second layers are formed by physical vapor deposition, atomic layer deposition, chemical vapor deposition, or plasma enhanced variations thereof.
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December 19, 2013
July 7, 2015
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